Mars sample return plan carries microbial risk, group warns

By Richard StengerCNN.com Writer

(CNN) -- Should NASA bring back Mars soil or rock to Earth? While the space agency hopes to accomplish that feat within the decade, the International Committee Against Mars Sample Return (ICAMSR) warns it could infect Earth with an interplanetary plague.

NASA unveiled in October a wish list of unmanned missions to Mars in
the early 21st century, culminating in several roundtrip flights that would bring home multi-kilogram chunks of the red planet. Terrestrial scientists would poke and prod the samples for evidence of past or present microbial life.

ICAMSR, a group of professional scientists and amateur space enthusiasts, thinks there is a chance that earthlings might find more than they bargained for. A Mars microbe could wreak havoc on terrestrial species, which would have no natural defenses against the alien invaders.

"If we make one mistake it could mean the extinction -- maybe for our species, or maybe another, for instance bumble bees or photoplankton, which are a huge part of our ecology," said ICAMSR founder Barry DiGregorio.

Many planetary scientists dismiss the risks as unwarranted or highly
exaggerated, saying the surface of Mars is most likely lifeless, anyway.

Moreover, the samples, once recovered from protective canisters that
land via parachute in the American desert, would be contained in
laboratories and handled as if they contained deadly and highly infectious organisms.

"NASA is taking the necessary precautions," said John Rummel, NASA's planetary protection
officer. The returned samples will be "kept in a controlled environment with as many precautions as possible."

Rummel points out that the Earth naturally receives geological samples
from Mars all the time. Dozens or hundreds of kilograms of martian
meteorites hit the planet each year. If martian microbes exist they
would have invaded Earth long ago, inoculating terrestrial life forms
in the process, according to Rummel and other planetary scientists.

DiGregorio remains undaunted.

"This is a great fallacy and it's unscientific as well," he said.

In fact, DiGregorio, the author of "Mars: The Living Planet," suggests
epidemics that originate in space might have already taken place. Mass
extinctions over the ages have been tied to giant meteorite or comet
strikes. But such cataclysms could perhaps be more fully explained, he
said, if science considers the possibility that extra-terrestrial
viruses played a role, for example when the age of the dinosaurs ended
65 million years ago.

"The dinosaurs did not die out that day. It took 2.5 million years for
them to go extinct. If the dinosaurs survived the initial impact, why
didn't they go on?" DiGregorio said.

Many are skeptical of DiGregorio, but fellow ICAMSR members include a handful of prominent scientists, like Chandra Wickramasinghe, one of the first to put forward the increasingly accepted theory that complex organic molecules riddle deep space. Another is Gilbert Levin, who designed experiments to detect life for Russian and U.S. Mars missions.

ICAMSR's Web site (www.icamsr.org) outlines NASA's plan and what the group sees as its inherent risks

Though most of his peers concluded otherwise, Levin still holds that the robot tests he coordinated on the 1976 Viking lander indicated the presence of living organisms on Mars. DiGregorio cites Levin's work as evidence that robots should poke around more for life on Mars before they return to Earth with samples.

Yet NASA plans to forego life detection experiments on missions for the
next 15 years or so. Only a European lander called Beagle 2 will sniff
the planet for signs of life. It is scheduled to arrive on the red planet in
about three years.

But NASA's Rummel said such tests would be insufficient. If microbes do exist on
Mars, experiments based on human understanding of life might be too
limited to detect them.

"Tests on Mars for life are not necessary because if it tests negative,
it still doesn't mean there is no life. And if it's positive, you
cannot possibly take more precautions than NASA plans," he said.

Such assurances do little to placate DiGregorio.

"We simply do not have the technology or the means yet to pull off a
safe sample return mission," he said. "Can we afford to make a mistake
with this, something that might carry a deadly virus?"